Bulk deposition of PAHs, PCBs and HCHs in Finland in summer seasons 1993–1996

Abstract

Aerial transport of organochlorines to Scandinavia as well as to Arctic areas has been observed in recent years. Atmospheric transport, wet and dry deposition and the tendency towards cold condensation are likely the major reasons for many organochlorine compounds being detected in nonpolluted northern areas. This paper presents the monthly collected bulk deposition results of PAHs (31 congeners), PCBs (6 congeners) and HCHs (3 congeners) from the summer seasons of 1993–1996. The detection limits for PAHs, PCBs and HCHs vary from 0.01 to 1 ng/1 and depositions were calculated as micrograms per square metre. The deposition of PAHs have been clearly decreasing both in Lapland and in southern Finland. The deposition of PCBs have been about three times larger in 1994 and 1995 than in 1993 or 1996 in Lapland. PCB deposition in 1995 was also two to three times larger than in other years in southern Finland. There have not been any trends in the deposition of HCHs in Lapland, but in Southern Finland HCH deposition has clearly been smaller from 1994–1995 than in other years.